dubious
The definition for dubious is "Questionable." Used in a sentence: Karl found Kevin's claim that he was sick dubious, as he had just seen him playing football.
exalt
The definition for exalt is "To elevate by praise." Used in a sentence: The fireman was publicly exalted for his heroism.
finite
The definition for finite is "Having definite limits." Used in a sentence: The exasperated mother had finite patience for her toddler's tantrums.
polarize
The definition for polarize is "To break up into opposing groups." Used in a sentence: Thelma tended to polarize discussions rather than to encourage compromise.
serenity
The definition for serenity is "Calmness." Used in a sentence: The serenity of the glassy sea soothed the sailors after the big storm.